Contra-tapered tank design for cross-counterflow radiator

ABSTRACT

The invention relates to a cross-counterflow heat exchanger, such as a cross-counterflow radiator for a motor vehicle, having an improved inlet/outlet tank wherein the inlet and outlet chambers are laterally off-set allowing the inlet and outlet ports to be oriented in the same general direction toward the fluid source; more particularly, the inlet and outlet chambers are tapered thereby providing improved flow distribution and pressure drop for fluid flow; still more particularly, the return tank inlet and outlet chambers are contra-tapered allowing the inlet and outlet ports to be substantially aligned resulting in a laterally compact heat exchanger.

TECHNICAL FIELD OF INVENTION

The invention relates to a cross-counterflow heat exchanger, such as across-counterflow radiator for a motor vehicle, having an improvedinlet/outlet tank wherein the inlet and outlet chambers arecontra-tapered, thereby allowing the inlet and outlet ports to extend inthe same general direction toward a fluid source.

BACKGROUND OF INVENTION

Cross-counter flow heat exchangers, such as a cross-counter flowradiator, are used to convey heat away from hot powertrain componentssuch as the engine, transmission, compressor, or even a fuel cell of anautomobile. With the advent of new powertrain cooling challenges, theneed for mass reduction, and the decreasing available space within theengine compartment of an automobile, cross-counter flow radiators arebecoming more desirable because of its higher cooling capacity per unitvolume.

A cross-counter flow radiator is part of a closed loop system whereinthe radiator is hydraulically connected to passageways within an engineor other powertrain heat source through which a heat transfer fluid,such as a mixture of water and ethylene glycol, is circulated. A streamof air is blown perpendicularly to a face of the radiator for heattransfer to the ambient air.

Shown in FIG. 1 is a typical cross-counter flow heat exchanger 100 knownin the art having a pair of opposed faces 105 a, 105 b, one facingtoward, and one away from, the source of heat of which is a vehicleengine here. The typical cross-counter flow heat exchanger 100 is formedof a central core 110 having a multitude of parallel tubes 115. Betweenthe tubes are typically fins 118 to increase the surface area foroptimal heat dissipation. FIG. 1A is a cut away top view of FIG. 1 alongsection line 1A. Shown in FIG. 1A is a tube partition 120 running alongthe interior length of one of the parallel tubes 115. A return tank 130is attached to core end 133 a, aligned with the parallel tube openings,and an inlet/outlet tank 135 is attached to the other core end 133 b.

Shown in FIG. 1A, the inlet/outlet tank 135 has a tank partition 140along the longitudinal axis 145, effectively dividing the tank into afirst chamber 150 a and a second chamber 150 b, wherein the firstchamber 150 a has an inlet port 155 a and the second chamber 150 bhaving an outlet port 155 b. The inlet/outlet tank 135 is mated to thecore end 133 b with a header plate 160 in between. The inlet/out tankpartition 140 cooperates with the header plate 160, tube partition 120,and return tank 130 to define first fluid passageways 125 a and secondfluid passageways 125 b.

The hot heat transfer fluid from the internal combustion engine flowsinto the first chamber 150 a by way of inlet port 155 a and then throughfirst passageways 125 a to return tank 130. Return tank 130 ishydraulically connected to second passageways 125 b through which theheat transfer fluid travels to second chamber 150 b before exitingoutlet port 155 b. As the hot fluid flows through passageways 125 a, 125b heat is released to the ambient air by convection. It should beappreciated that the heat transfer fluid flows in substantially parallelbut counter directional paths in the first passageways 125 a along firstface 105 a and in the opposite direction through second passageways 125b along the opposed second face 105 b.

Unlike conventional cross flow radiators, cross-counterflow radiatorshave the inlet and outlet ports at the same end of the heat exchangercore. The engine is the hot fluid source 165 supplying the cross-counterflow heat exchanger. FIG. 1 shows a prior art design where the inlet andoutlet extend in the same direction laterally outward from inlet/outlettank, not toward fluid source 165.

FIG. 2 is a perspective view of another prior art cross-counter flowradiator 200 design where the inlet port 255 a and outlet port 255 bextend in opposing directions on inlet/outlet tank 235. Inlet port 255 aextends toward the engine, the fluid source 220; however, outlet port255 b extends directly away from the fluid source 220.

A disadvantage of the prior art inlet/outlet tanks 135, 235 is thatadditional hardware such as elbows, hoses, clamps, and fittings arerequired to orient either the inlet ports 155 a, 255 a or outlet ports155 b, 255 b toward the fluid source 165, 220. This results inadditional space utilization, weight, plumbing hardware, potential leakpoints, labor, and associated cost.

Furthermore, the inlet/outlet tank designs 135, 235 shown in FIG. 1 andFIG. 2 are substantially uniform in cross sectional area and functionprimarily as manifolds for distribution of heat transfer fluid acrossthe central cores 110, 210. It is known in the art that tapered tanksprovide a more desired fluid flow profile across the central core 110,210.

For design criteria where space is limited, such as the enginecompartment of a modern vehicle, there exists a need for a cross-counterflow heat exchanger that is compact, robust, economical to manufacture,and provides the same desired fluid flow distribution and pressure dropadvantages as those of tapered tanks.

SUMMARY OF THE INVENTION

The invention relates to a cross-counterflow heat exchanger, such as across-counterflow radiator for a motor vehicle, having an improvedinlet/outlet tank wherein the inlet and outlet chambers arecontra-tapered, thereby allowing the inlet and outlet ports to extend inthe same general direction toward the fluid source, and provide improvedflow distribution and pressure drop for fluid flow.

The cross-counterflow fluid heat exchanger has a central core with twoopposing lateral faces and two opposing core ends. The central core isconstructed from a plurality of substantially parallel liquid flow tubeswith fins in between the tubes for improved heat dissipation and addedstructural integrity. The flow tubes have an internal lengthwisepartition defining a plurality of first fluid passageways along one faceand a plurality of second fluid passageways along the opposed face. Theheat exchanger is supplied with heated fluid from a fluid source, suchas that of an internal combustion engine of a motor vehicle, locatedspaced apart from one of the opposed faces.

A return tank is attached to one end of the central core correspondingto the flow tube openings at one core end and an inlet/outlet tank isattached to the opposite end of the parallel tube openings. Theinlet/outlet tank has a first chamber that hydraulically communicateswith the first fluid passageways and a second chamber that hydraulicallycommunicates with the second fluid passageways.

Unlike a conventional inlet/outlet tank, which has a single lateral orside surface facing the engine, each chamber in the inlet/outlet tank ofthe subject invention has a distinct lateral surface, offset from theplane of the other, and large enough to allow a port to extend therefromin the same direction, toward the engine, without interference with theother chamber or port. In addition, in the embodiment disclosed, eachchamber of the inlet/outlet tank is contra-tapered, that is, tapered inthe opposite direction from the other chamber. This shape provides theoffset lateral surfaces that are both wide enough to allow the desiredlocation and orientation of the ports, as well as providing for improvedflow distribution.

An advantage of the present invention is that the inlet and outlet portopenings extend in the same general direction toward the fluid source.This preferred orientation of the inlet/outlet ports eliminates the needfor additional plumbing hardware such as elbows, hoses, clamps, andfittings to redirect the heat exchange fluid flow toward the fluidsource, thereby resulting in less weight and reduced potential leakpoints.

A further advantage of contra-tapering the chambers of the inlet/outtank toward the central core opposing surfaces is that this provides acompact inlet/outlet tank design resulting in a laterally compact heatexchanger. A compact inlet/outlet tank design also allows for lessercoolant usage resulting in additional weight savings.

A still further advantage is that the contra tapered chambers provideimproved flow distribution and pressure drop for the heat exchange fluidas it flows through the central core. This allows for even more compactheat exchanger design due to greater increase efficiency of the heatexchanger.

The features and advantages of the present invention will becomeapparent to those skilled in the art from analysis of the followingwritten description, the accompanying drawings and claims.

BRIEF DESCRIPTION OF DRAWINGS

This invention will be further described with reference to theaccompanying drawings in which:

FIG. 1 is a perspective view of a cross-counterflow heat exchangershowing an inlet and outlet extending from a common exterior surface ofan inlet/outlet tank in a direction that is perpendicular to the fluidsource.

FIG. 1A is a cut away top view of FIG. 1 along section line 1A showingdirections of fluid flow.

FIG. 2 is a perspective view of a cross-counterflow heat exchangershowing an inlet and outlet extending from opposing surfaces of aninlet/outlet tank.

FIG. 3 is a perspective view of a cross-counterflow heat exchanger, inaccordance with the invention, showing an inlet and outlet extendingtoward the fluid source.

FIG. 3A is a cut away top view of FIG. 3 along elevation section 3Ashowing directions of fluid flow, in accordance with the invention.

FIG. 4 is an end view of the inlet/outlet tank detailing the interiorsurfaces with the inlet and outlet extending from the same surface, inaccordance with the invention.

FIG. 5 is a side view of the inlet/outlet tank showing tapered chamberlateral exterior surfaces, in accordance with the invention.

FIG. 6 is a perspective view of the inlet/outlet tank, in accordancewith the invention.

DETAILED DESCRIPTION OF INVENTION

Shown in FIGS. 3 through 6, in accordance with a preferred embodiment ofthis invention, is a cross-counter flow heat exchanger such as across-counter flow radiator utilized to cool an internal combustionengine of an automobile.

FIG. 3 is a perspective view of cross-counterflow heat exchanger 300having a central core 305 with opposing faces 310 a, 310 b, one facingtoward, and one away from hot fluid source 345. Fluid source 345, inthis case, would be an internal combustion engine of a motor vehicle(not shown). Both of the opposed faces 310 a, 310 b are situatedsubstantially perpendicular to hot fluid source 345. Central core 305has a plurality of substantially parallel liquid flow tubes 315 forconveyance of heat exchange fluid. Fins 318 are inter-disposed betweenflow tubes 315 for improved heat dissipation and increased structuralintegrity. Outer flow tubes 315 of central core 305 are bounded by firstsupport member 314 a and a second support member 314 b. First and secondsupport members 314 a, 314 b are both substantially parallel with flowtubes 315.

FIG. 3A is a cut away top view of FIG. 3 along elevation line 3A showingdirections of fluid flow through flow tubes 315. Shown along theinterior length of flow tubes 315 is partition 320 defining first fluidpassageways 325 a and second fluid passageways 325 b. Flow tubes 315 andpartitions 320 can be manufactured as an integral extrusion orfabricated from flat stock.

In reference to both FIGS. 3 and 3A, return tank 330 is attached to anend of the central core corresponding to the flow tube openings 319 b.Inlet/outlet tank 335 is attached to the opposite end of the centralcore corresponding to flow tube openings 319 a. Inlet/outlet tank 335has first inlet/outlet port 340 a and second inlet/outlet port 340 bextending from a same side surface in a direction generally toward fluidsource 345.

In reference to FIG. 4 through 6, inlet/outlet tank 335 has longitudinalaxis 355 along interior length of inlet/outlet tank 335. Inlet/out tank335 has internal partition 350 along longitudinal axis 355 cooperatingwith interior surface 360 to define first chamber 365 a and secondchamber 365 b. First chamber 365 a and second chamber 365 b arecontra-tapered, that is, tapered in the opposite direction from theother chamber. Contra-tapering of first chamber 365 a and second chamber365 b provides for improved flow distribution and pressure drop forfluid flow through the central core. Contra-tapering of chambers 365 a,365 b also provides for distinct external features for inlet/outlet tank335 that allow for inlet/outlet ports 340 a, 340 b to be orientatedtoward fluid source 345.

The external features of first chamber 365 a include lateral exteriorsurface 370 a and exterior end edge 375 a. The external features ofsecond chamber 365 b include lateral exterior surface 370 b and exteriorend edge 375 b. First and second chambers' lateral exterior surfaces 370a, 370 b are both laterally offset, as well as offset from the plane ofthe other. Both lateral exterior surfaces 370 a, 370 b face fluid source345 and are wide enough to allow the desired location and orientation ofinlet/outlet ports 340 a, 340 b.

In reference to FIG. 4, defining the opening of inlet/outlet tank 335 isexterior perimeter edge 362. In reference to FIG. 5, the shape of firstchamber lateral exterior surface 370 a is substantially triangular,wherein the latitudinal distance W between first chamber exterior edge375 a and exterior perimeter edge 362 by first support member 314 a isgreater than the latitudinal distance Z between first chamber exterioredge 375 a and exterior perimeter edge 362 by second support member 314b.

The shape of the second chamber lateral exterior surface 370 a is alsosubstantially triangular; however, a portion of second chamber lateralexterior surface 370 is obscured by first chamber 365 a. The latitudinaldistance Y between second chamber exterior end edge 375 b and exteriorperimeter edge 362 by first support member 314 a is less than thelatitudinal distance X between said second chamber exterior end edge 375b and exterior perimeter edge 362 by second support member 314 b.

Shown in FIG. 5, the overall shape of first and second chamber lateralexterior surfaces 370 a, 370 b, when view from fluid source 345, isessentially that of two overlapping right triangles sharing a commonleg, wherein the right angle of each triangle opposes each other.Protruding from the first chamber lateral exterior surface 370 a is afirst inlet/outlet port 340 a and protruding from the second chamberlateral exterior surface 370 b is a second inlet/outlet port 340 b. Bothof the inlet/outlet ports 340 a, 340 b extend in the same generaldirection toward fluid source 345 and are also substantially alignedlongitudinally. This preferred orientation of inlet/outlet ports 340 a,340 b eliminates the need for additional plumbing hardware such aselbows, hoses, clamps, and fittings to redirect the heat exchange fluidflow toward the fluid source.

Contra-tapering first and second chambers 365 a, 365 b of inlet/out tank335 also provides for an overall laterally compact inlet/outlet tankdesign. Furthermore, tapered chambers provide improved flow distributionand pressure drop for the heat exchange fluid as it flows throughcentral core 305 and thereby increases the heat transfer efficiency ofthe heat exchanger.

In reference to FIG. 3A, the hot heat transfer fluid from the internalcombustion engine flows into the first chamber 365 a by way of firstinlet/outlet port 340 a and then through first passageways 325 a toreturn 330 tank. Return tank 330 is hydraulically connected to secondpassageways 325 b through which the heat transfer fluid travels tosecond chamber 365 b before exiting inlet/outlet port 340 b. As the hotfluid flows through passageways 325 a, 325 b in parallel but oppositedirection, heat is released to the ambient air by convection.

While this invention has been described in terms of the preferredembodiments thereof, it is not intended to be so limited, but ratheronly to the extent set forth in the claims that follow.

1. In a cross-counterflow fluid heat exchanger with a pair of opposedfaces having: a heat exchanger core with a plurality of liquid flowtubes, wherein said tubes have a lengthwise partition defining a firstfluid passageway along one face and a second fluid passageway along theopposed face; and in which said heat exchanger is supplied with fluidfrom a source located spaced from one of said opposed faces, theimprovement comprising, an inlet/outlet tank on one end of said corehaving: a first chamber hydraulically communicating with said firstfluid passageway; a second chamber hydraulically communicating with saidsecond fluid passageway; a first chamber lateral exterior surface facingsaid fluid source; a second chamber lateral exterior surface facing saidfluid source, wherein one of said chamber lateral exterior surfacesextends beyond the other; a first inlet/outlet port through said firstchamber lateral exterior surface and extending generally toward saidfluid source; and a second inlet/outlet port through said second chamberlateral exterior surface and also extending generally toward said fluidsource.
 2. A cross-counterflow fluid heat exchanger of claim 1 whereinsaid first chamber lateral exterior surface and said second chamberlateral exterior surface are on off-set substantially parallel planes.3. A cross-counterflow fluid heat exchanger of claim 2 wherein at leastone of said chamber lateral exterior surfaces is tapered.
 4. Across-counterflow fluid heat exchanger of claim 2 wherein said firstchamber lateral exterior surface and said second chamber lateralexterior surface are contra-tapered.
 5. A cross-counterflow fluid heatexchanger of claim 2 wherein at least one of said chambers is tapered.6. A cross-counterflow fluid heat exchanger of claim 2 wherein saidfirst chamber and said second chamber are contra-tapered.
 7. Across-counter flow fluid heat exchanger of claim 1 wherein: said heatexchanger core further comprises a first support member and a secondsupport member bounding either side of said core, wherein said supportmembers are substantially parallel with said flow tubes; and saidinlet/outlet tank further comprising of: an elongated cavity having aninterior surface and an exterior perimeter edge along open face ofcavity, a longitudinal axis along length of cavity; a partition alonglongitudinal axis together with said interior surface defining saidfirst chamber and said second chamber; a first chamber exterior edgeconnected to said first chamber exterior surface; and a second chamberexterior edge connected to said second chamber exterior surface; whereinthe distance W between said first chamber exterior edge and saidexterior perimeter edge by said first support member is greater than thedistance Z between said first chamber exterior edge and said exteriorperimeter edge by said second support member end; and wherein thedistance Y between said second chamber exterior edge and said exteriorperimeter edge by said first support member is less than the distance Xbetween said second chamber exterior end edge and said exteriorperimeter edge near second support member.
 8. A cross-counter flow fluidheat exchanger of claim 7 wherein said first chamber lateral exteriorsurface and second chamber lateral exterior surface are substantiallytriangular in shape.
 9. A cross-counter flow fluid heat exchanger ofclaim 1 wherein said fluid source is an internal combustion engine. 10.In a cross-counterflow fluid heat exchanger with a pair of opposed facesfor an internal combustion engine having: a heat exchanger core with aplurality of liquid flow tubes, wherein said tubes have a lengthwisepartition defining a first fluid passageway along one face and a secondfluid passageway along the opposed face; and in which said heatexchanger is supplied with fluid from a source located spaced from oneof said opposed faces, the improvement comprising: an inlet/outlet tankon one end of said core having: a first chamber hydraulicallycommunicating with said first fluid passageway; a second chamberhydraulically communicating with said second fluid passageway; a firstchamber lateral exterior surface facing said engine; a second chamberlateral exterior surface facing said engine, wherein one of said chamberlateral exterior surfaces extends beyond the other; a first inlet/outletport through said first chamber lateral exterior surface and extendinggenerally toward said engine; and a second inlet/outlet port throughsaid second chamber lateral exterior surface and also extendinggenerally toward said engine.
 11. A cross-counterflow fluid heatexchanger of claim 10 wherein said first chamber lateral exteriorsurface and said a second chamber lateral exterior surface are onoff-set substantially parallel planes.
 12. A cross-counterflow fluidheat exchanger of claim 11 wherein at least one of said chambers istapered.
 13. A cross-counterflow fluid heat exchanger of claim 12wherein said first chamber and said second chamber are contra-tapered.